Rezso Zoller

Depressive Symptoms and Mortality in Patients After Kidney Transplantation: A Prospective Prevalent Cohort Study

Objective: To analyze in a prospective cohort study if depressive symptoms are an independent predictor of mortality in kidney transplant recipients. Methods: Data from 840 transplanted patients followed at a single outpatient transplant center were analyzed. Sociodemographic parameters and clinical data were collected at enrollment (between August 2002 and February 2003). Participants completed the Center for Epidemiologic Studies-Depression (CES-D) scale. Depression was defined as CES-D score of ≥18. Data on 5-year outcomes (death censored graft loss or mortality) were collected. Results: The prevalence of depression was 22%. Mortality was higher (21% versus 13%; p = .004) in patients with versus without depression. In a multivariate Cox proportional hazard model, both the baseline CES-D score (hazard ratiofor each 1-point increase = 1.02; 95% confidence interval, 1.00–1.04) and the presence of depression at baseline (hazard ratiopresence = 1.66; 95% confidence interval, 1.12–2.47) were significantly associated with mortality. The baseline CES-D score also significantly predicted death censored graft loss (hazard ratiofor each 1-point increase = 1.03; 95% confidence interval, 1.01–1.05). Conclusion: Depressive symptoms are an independent predictor of mortality in kidney transplanted patients. CES-D = Center for Epidemiologic Studies-Depression scale; CKD = chronic kidney disease; CNI = calcineurin inhibitor; CRP = C-reactive protein; CsA = cyclosporine A; DOPPS = Dialysis Outcomes and Practice Patterns Study; GFR = estimated glomerular filtration rate; ESRD = end-stage renal disease; ESRD-SI = End-Stage Renal Disease Severity Index; Hb = hemoglobin; HLA = human leukocyte antigen; HR = hazard ratio; IQR = interquartile range.

Association between restless legs syndrome and depression in patients with chronic kidney disease.

Restless legs syndrome (RLS) is reportedly associated with depression. This association may be mediated by both sleep-dependent and sleep-independent mechanisms. Here we analyze the association between RLS and depressive symptoms in patients with chronic kidney disease (CKD). We also assessed whether the relationship is independent of insomnia. In a cross-sectional study, socio-demographic parameters, laboratory data, and medical history were collected from 788 kidney transplant patients and 161 dialyzed patients. Insomnia, depression, and the presence of RLS symptoms were assessed with standard questionnaires. Patients with probable RLS had a higher prevalence of depressive symptoms than those without RLS (56% vs. 22% with vs. without RLS, respectively; P<.001). Patients presenting RLS symptoms had higher Athens Insomnia Scale (AIS) scores than patients without RLS [median AIS score (interquartile range): 7 (6) vs. 3 (4) with vs. without RLS, respectively; P<.001]. The AIS score correlated with the CES-D score (Spearmans rho=0.54, P<.001). In multivariate analysis, the presence of RLS symptoms was independently associated with depressive symptoms (OR=3.96, 95% CI 2.21-7.1, P<.001). This relationship remained significant even after including insomnia in the model (OR=2.9, CI 1.55-5.43, P<.001). The presence of RLS symptoms is associated with depression in patients with CKD. This relationship remained significant even after accounting for insomnia. Sleep-independent mechanisms may also contribute to the association between RLS and depression in patients with CKD.

Periodic limb movements in sleep are associated with stroke and cardiovascular risk factors in patients with renal failure

Periodic limb movements in sleep (PLMS) is prevalent among dialysed patients and is associated with increased risk of mortality. Our study aimed to determine the prevalence of this disease in a sample of transplanted and waiting‐list haemodialysed patients. One hundred transplanted and 50 waiting‐list patients underwent polysomnography. Moderate and severe diseases were defined as periodic limb movements in sleep index (PLMSI) higher than 15 and 25 events h−1, respectively. The 10‐year coronary heart disease risk was estimated for all patients using the Framingham Score. Moreover, the 10‐year estimated risk of stroke was calculated according to the modified version of the Framingham Stroke Risk Profile. PLMS was present in 27% of the transplanted and 42% of the waiting‐list group (P = 0.094); the proportion of severe disease was twice as high in waiting‐list versus transplanted patients (32 versus 16%, P = 0.024). Patients with severe disease had a higher 10‐year estimated risk of stroke in the transplanted group [10 (7–17) versus 5 (4–10); P = 0.002] and a higher 10‐year coronary heart disease risk in both the transplanted [18 (8–22) versus 7 (4–14); P = 0.002], and the waiting‐list groups [11 (5–18) versus 4 (1–9); P = 0.032]. In multivariable linear regression models the PLMSI was associated independently with the Framingham cardiovascular and cerebrovascular scores after adjusting for important covariables. Higher PLMSI is an independent predictor of higher cardiovascular and cerebrovascular risk score in patients with chronic kidney disease. Severe PLMS is less frequent in kidney transplant recipients compared to waiting‐list dialysis patients.

Sleep apnea is associated with cardiovascular risk factors among kidney transplant patients.

BACKGROUND AND OBJECTIVES We assessed the prevalence of obstructive sleep apnea (OSA) and its clinical correlates in a large sample of patients who received a kidney transplant (Tx). We also compared the prevalence of the disorder between dialysis patients who were on the waiting list for a Tx (WL) and Tx patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This was a cross-sectional study of 100 Tx and 50 WL patients who underwent one-night polysomnography (SLeep disorders Evaluation in Patients after kidney Transplantation [SLEPT] Study). Sociodemographic information and data about medication, comorbidity, and laboratory parameters were collected. RESULTS The prevalence of mild (apnea-hypopnea index [AHI] > or =5/h and <15/h), moderate (AHI > or =15/h and <30/h), and severe OSA (AHI > or =30/h) was 18, 11, and 14% in the Tx group and 28, 16, and 10% in the WL group, respectively. The AHI was significantly correlated with age (rho = 0.34), body mass index (rho = 0.45), neck circumference (rho = 0.4), abdominal circumference (rho = 0.51), and hemoglobin (rho = 0.24) in the Tx group. The proportion of Tx patients who were treated with three or more antihypertensive drugs was significantly higher in the OSA group (56 versus 31%; P = 0.022). Despite taking significantly more antihypertensive drugs, the average systolic BP was still higher in patients with versus without OSA (147 +/- 21 versus 139 +/- 18 mmHg; P = 0.059). CONCLUSIONS The prevalence of OSA is similar in Tx and WL patients and it may contribute to presence of hypertension in patients who receive a Tx.

Socio-demographic characteristics, health behaviour, co-morbidity and accidents in snorers: a population survey

ObjectiveWe assessed the socio-demographic correlates of snoring and also the patterns of health behaviour and co-morbidity associated with different types of snoring in the Hungarian population. We wanted to study whether different types of snoring are associated with high-risk health behaviour, chronic illnesses, daytime consequences of poor sleep, and with frequent accidents compared with non-snoring individuals.MethodThis is a cross-sectional study. Interviews were carried out in the homes of 12,643 people. This was the largest nationally representative study in Central Europe about health behaviour. In the Athens Insomnia Scale, questions about snoring and sleep behaviour, life-style factors and health behaviour, as well as questions on their history and current medical treatment were included in the questionnaire.ResultsThirty-seven percent of males and 21% of females reported loud snoring with breathing pauses. We found a significant increasing trend for the consumption of alcohol and coffee as well as smoking among non-snorers, habitual snorers and loud snorers, respectively. In an ordinal regression model male gender, the presence of smoking, the presence of three or more co-morbid conditions and alcohol consumption were independent predictors of snoring (OR [95% CI], 1.99 [1.85–2.1], 1.76 [1.60–1.92], 1.45 [1.30–1.62] and 1.22 [1.04–1.43], respectively, P < 0.001) after controlling for multiple socio-demographic and clinical variables. The frequency of accidents was higher in the loud snoring group than among non-snoring individuals (24% vs 17%, P < 0.0001).ConclusionsSnoring is common in the Hungarian adult population. Snoring, especially loud snoring with breathing pauses, is strongly associated with high-risk health behaviour, higher co-morbidity and a higher frequency of accidents.

Obstructive Sleep Apnea and Heart Rate Variability in Male Patients with Metabolic Syndrome: Cross-Sectional Study

BACKGROUND Obstructive sleep apnea (OSA) is often accompanied by the metabolic syndrome. Because both conditions are associated with depressed heart rate variability (HRV) separately, our aim was to study whether co-morbid OSA is associated with more reduced HRV in male patients with the metabolic syndrome. METHODS In this cross-sectional study, 35 men (age, 57±11 years) with the metabolic syndrome (according to International Diabetes Federation criteria) were included. OSA severity was defined by the apnea-hypopnea index (AHI). HRV was assessed by 24-hr ambulatory electrocardiographic monitoring. Standard deviation of all normal-to-normal RR intervals (SDNN), the high frequency power (HFP), and the ratio of low- to high-frequency power (LF/HF) were measured. RESULTS There were 14, 6, and 8 cases of severe (AHI ≥30/hr), moderate (15/hr≤AHI <30/hr), and mild (5/hr ≤AHI <15/hr) OSA, respectively. Seven patients had no OSA. Patients with mild-moderate or severe OSA had reduced SDNN and HFP values compared to those without OSA. Increasing OSA severity was associated significantly with lower daytime LF/HF ratio [standardized β regression coefficient (β)=-0.362, P=0.043] and higher night/day LF/HF ratio (β=0.377, P=0.023) after controlling for age, duration of diabetes, and severity of metabolic syndrome. CONCLUSIONS Co-morbid OSA is associated with decreased overall HRV, parasympathetic loss, and impaired diurnal pattern of sympathovagal balance that may further increase the cardiovascular vulnerability of male patients with the metabolic syndrome. The role of the HRV analysis in the risk assessment of these patients warrants further studies.

Association of symptoms of insomnia and sleep parameters among kidney transplant recipients

OBJECTIVE Insomnia complaints are frequent among kidney transplant (kTx) recipients and are associated with fatigue, depression, lower quality of life and increased morbidity. However, it is not known if subjective insomnia symptoms are associated with objective parameters of sleep architecture. Thus, we analyze the association between sleep macrostructure and EEG activity versus insomnia symptoms among kTx recipients. METHODS Participants (n1=100) were selected from prevalent adult transplant recipients (n0=1214) followed at a single institution. Insomnia symptoms were assessed by the Athens Insomnia Scale (AIS) and standard overnight polysomnography was performed. In a subgroup of patients (n2=56) sleep microstructure was also analyzed with power spectral analysis. RESULTS In univariable analysis AIS score was not associated with sleep macrostructure parameters (sleep latency, total sleep time, slow wave sleep, wake after sleep onset), nor with NREM and REM beta or delta activity in sleep microstructure. In multivariable analysis after controlling for covariables AIS score was independently associated with the proportion of slow wave sleep (β=0.263; CI: 0.026-0.500) and REM beta activity (β=0.323; CI=0.041-0.606) (p<0.05 for both associations). CONCLUSIONS Among kTx recipients the severity of insomnia symptoms is independently associated with higher proportion of slow wave sleep and increased beta activity during REM sleep but not with other parameters sleep architecture. The results suggest a potential compensatory sleep protective mechanism and a sign of REM sleep instability associated with insomnia symptoms among this population.